FastJet  3.0.6
FunctionOfPseudoJet.hh
1 #ifndef __FASTJET_FUNCTION_OF_PSEUDOJET_HH__
2 #define __FASTJET_FUNCTION_OF_PSEUDOJET_HH__
3 
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5 // $Id: FunctionOfPseudoJet.hh 2577 2011-09-13 15:11:38Z salam $
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31 
32 #include <fastjet/PseudoJet.hh>
33 #include <fastjet/Selector.hh>
34 
35 FASTJET_BEGIN_NAMESPACE
36 
37 /// \class FunctionOfPseudoJet
38 /// base class providing interface for a generic function of a PseudoJet
39 ///
40 /// This class serves as a base class to provide a standard interface
41 /// for a function that returns an object of a given (templated) type
42 /// that depends on a PseudoJet argument. The rationale for using a
43 /// class (rather than a pointer to a function) is that a class can be
44 /// constructed with (and store) additional arguments.
45 template<typename TOut>
47 public:
48  /// default ctor
50 
51  /// ctor that creates a constant function
52  FunctionOfPseudoJet(const TOut &constant_value);
53 
54  /// default dtor (virtual to allow safe polymorphism)
56 
57  /// returns a description of the function (an empty string by
58  /// default)
59  virtual std::string description() const{ return "";}
60 
61  /// the action of the function
62  /// this _has_ to be overloaded in derived classes
63  /// \param pj the PseudoJet input to the function
64  virtual TOut result(const PseudoJet &pj) const = 0;
65 
66  /// apply the function using the "traditional" () operator.
67  /// By default, this just calls the apply(...) method above.
68  /// \param pj the PseudoJet input to the function
69  TOut operator()(const PseudoJet &pj) const { return result(pj);}
70 
71  /// apply the function on a vector of PseudoJet, returning a vector
72  /// of the results.
73  /// This just calls apply on every PseudoJet in the vector.
74  /// \param pjs the vector of PseudoJet inputs to the function
75  std::vector<TOut> operator()(const std::vector<PseudoJet> &pjs) const {
76  std::vector<TOut> res(pjs.size());
77  for (unsigned int i=0; i<pjs.size(); i++)
78  res[i] = result(pjs[i]);
79  return res;
80  }
81 };
82 
83 // The following functions will not be for FJ3.0, because passing a
84 // reference does not work when the argument is a temporary, which can
85 // lead to hard-to-diagnose run-time errors. A workaround is to to
86 // have a pointer rather than a reference as argument, since this
87 // provides a clearer signal to the user that the object must remain
88 // in scope.
89 //
90 //
91 // // Selectors created from the ordering between a FunctionOfPseudoJet
92 // // and a constant
93 // //----------------------------------------------------------------------
94 //
95 // /// 'larger than' operator
96 // ///
97 // /// Select jets for which the given function returns a result larger
98 // /// than the specified constant
99 // Selector operator >(const FunctionOfPseudoJet<double> & fn, const double & cut);
100 //
101 // /// 'smaller than' operator
102 // ///
103 // /// Select jets for which the given function returns a result smaller
104 // /// than the specified constant
105 // Selector operator <(const FunctionOfPseudoJet<double> & fn, const double & cut);
106 //
107 // /// 'larger or equal' operator
108 // ///
109 // /// Select jets for which the given function returns a result larger or equal
110 // /// to the specified constant
111 // Selector operator >=(const FunctionOfPseudoJet<double> & fn, const double & cut);
112 //
113 // /// 'smaller or equal' operator
114 // ///
115 // /// Select jets for which the given function returns a result smaller or equal
116 // /// to the specified constant
117 // Selector operator <=(const FunctionOfPseudoJet<double> & fn, const double & cut);
118 
119 
120 FASTJET_END_NAMESPACE
121 
122 #endif // __FASTJET_FUNCTION_OF_PSEUDOJET_HH__
fastjet::FunctionOfPseudoJet::FunctionOfPseudoJet
FunctionOfPseudoJet()
default ctor
Definition: FunctionOfPseudoJet.hh:49
fastjet::FunctionOfPseudoJet
Definition: FunctionOfPseudoJet.hh:46
fastjet::PseudoJet
Definition: PseudoJet.hh:65
fastjet::FunctionOfPseudoJet::operator()
TOut operator()(const PseudoJet &pj) const
apply the function using the "traditional" () operator.
Definition: FunctionOfPseudoJet.hh:69
fastjet::FunctionOfPseudoJet::~FunctionOfPseudoJet
virtual ~FunctionOfPseudoJet()
default dtor (virtual to allow safe polymorphism)
Definition: FunctionOfPseudoJet.hh:55
fastjet::FunctionOfPseudoJet::description
virtual std::string description() const
returns a description of the function (an empty string by default)
Definition: FunctionOfPseudoJet.hh:59
fastjet::FunctionOfPseudoJet::operator()
std::vector< TOut > operator()(const std::vector< PseudoJet > &pjs) const
apply the function on a vector of PseudoJet, returning a vector of the results.
Definition: FunctionOfPseudoJet.hh:75